The type used when any slice of the original range of characters is used. If the range was a string or supports slicing, then SliceOfR is the same type as the range; otherwise, it's the result of calling $(PHOBOS_REF takeExactly, std, range) on it.
import std.algorithm : filter; import std.range : takeExactly; static assert(is(DOMEntity!string.SliceOfR == string)); auto range = filter!(a => true)("some xml"); static assert(is(DOMEntity!(typeof(range)).SliceOfR == typeof(takeExactly(range, 42))));